Electrically-actuated refrigerating machine



Nov. 1l, 1930. E. RUEGGER ELECTRICALLY ACTUATED RFRIGERATING MACHINE Filed May 19. 1927 .l/. .ll/l 'lll/lllllllll/ Patented Nov. 11,1930

UNITED STATES PATENToFFi/ca EDUARD REGGER, OF ZURICH, SWITZERLAND, ASSIGNOR T0 THE FIRM 4AKTIENGE- SELLSCHAFT DER MASCHINENFABRIKEN ESCHER WYSS & CIE., OF ZURICH, SWIT- ZERLAN D ELECTRIGALLY-AGTUATED REFRIGERATING MACHINE Application illed Hay 19, 1927, Serial No. 192,648, and in Switzerland lay 28, 1926.

This invention relates to partition walls or capsules for the gastight separation of rotor from stator in motors employed to operate the compressors of electrically driven refrigerating machines. `As materials for the construction of such capsules, non-magnetic steel alloys having ahigh electrical resistance have already been` employed.

As partition walls or capsules of this kind must, for constructional reasons, be made very thin, it is necessary for the material employed in their manufacture, to possess a great specific strength 'and strong power of resistance to corrosionand attack by acids, since the slightest rusting or the least erosion by acids renders the wall useless. The highly alloyed steels used hitherto for the manufacture of such-capsules fail to satisfy the .requirements above mentioned, more particularly as they are subject to molecular disintegration and consequent cracking under the influence of. local attack due to; atmospheric iniiuences or the presence of acids.

The-object of the present invention is'to eliminate the defects aforesaid and, to this ,end, the/ capsule is made from a steel alloy7 containing 9 to 22% chromium, 33-5% nickel and less thanv 1% carbon. Such an alloy, in addition to the properties of roviding satisfactory electrical conditions, beingnon-magnetic and possessing-a relatively high electrical resistance, has also a greatspeciic strength and great ductility as well, and it presents the further advantages of being very resistant to corrosion and attack by acids. Moreover, it can be subjected to such a heat treatment that after this treatment vit does not deteriorate as might otherwise occur under certain influences (e. g. temperature,

stresses arising during manufacture, electric currents and the like) in consequence ofl Ythe allcy is particularly adapted for the manufacture of capsules of the kind under driving a machine which is completely en closed in a suitable casing and y Fig. 2 is a section through the partition-A wall or 'capsule wall, drawn to a larger scale.

The numeral 3 designates the stator of an electric motor and 2 the rotor thereof. Between these two members 2 and 3 is interposed a cap or capsule '4 servin as a partition wall. At 25 this capsule ma es a gastight joint with a part 26 of a completely gastight closed housing 5 which surrounds a second housing?. In the latter is arranged a compressor 6 swingable about trunnions 8 and driven by means of a shaft 1 by the electric motor 2, 3. This compressor 6 draws refrigerating medi-um from a space 19, compresses it and delivers it into a space 9 from where it flows through a pipe 10into a chamber 11 and from there through a pipe 12 into'the annular space 13 formed between the housings 5 land 7. In the annular space 13 the refrigerating medium is liqueed; the liquid refrigeratingmedium collects in the Aspace 20, which is provided in its lower part with a pressure reducing device 17a. The flow of the liquid refrigerating medium to the lthrottling o ening 17a is controlled by a float 17. The re rigeratinjg medium expanding in the pressure reducing device 17a flows into a displacement .chamber 22 which is in open connection with the cvaporating chamber 23 at its lower end and by means of holes 24. The casing 15 of the evaporator is provided with ribs 16. The evaporating chamber 23is in connection with the above-mentioned space 19 by means of a pipe 18, the part ofthe latter situated inthe space 20 is formed as a coil 21. It is assumed that the operation of the machine will be understood. from the above description of its parts without any ifurther explanation.l

The capsule 4 is made from an alloy ofthe constitutlon abov'estated. The interposition ,of a steel capsule 4 between the stator 3 and the rotor 2 of an electric-motor results in the air gap between the poles of the stator and the material of the rotor being'substantially wider than in the case of a motor having .no

such capsule. Considerab e electrical losses are introduced in consequence of this. Now since the proposed chromelnickel-steel alloy possesses an 'extraordinarily great specific strength and great ductility as well, it becomes possible to make that part 410i the capsule which isvinterposed between the magnet poles o the stator 2 and the materialof the rotor thinner` than the rest `of the capsule as is shown in Fig. 2, that is to say, these otherv parts-can be made substantially thicker. By adopting such a construction for the capsule it becomes possibleto maintain a satisfactor degree of efficiency in the motor with lv vhic the device is employed.

I claim: v v '1. An electric motor. having a rotor and a Istator, a metal capsule, having a portion of reduced thickness in the air gap between the rotor and stator, said metal being a steel alloy containing 9% to 22% chromium, 33% to 5% nickel and less than 1% carbon and annealed after manufacture, of low magnetic properties, high specific strength, duCtile,re

sistant to molecular disintegration and highly resistant to corrosion and acid attack. v

2. An electric motor having a rotor and a stator, a :drawn metal capsule having a portion of reduced thickness in lthe air gap between the rotor and stator,.s aid metal capsule being an'alloy steel-containin g chromium about 9% to 22%, a high nickel content of of about 33% to 5% and a' carbon content be- 1owv1% annealed after manufacture, having low magnetic pro erties, high specific strength, ductile, reslstant to molecular dis integration andl 'highlyresistant to corroslon and acid attack.

In' testimony '1whereof,i I xhave signed my name to this specification.

.EDUARD REGGEB. 

